class_docstr: Base class for PCA methods.
  
  Warning: This class should not be used directly.
  Use derived classes instead.
class_docstr_tok: ["Base","class","for","PCA","methods",".","Warning",":","This","class","should","not","be","used","directly",".","Use","derived","classes","instead","."]
docstr: Placeholder for fit. Subclasses should implement this method!
  
  Fit the model with X.
  
  Parameters
  ----------
  X : array-like of shape (n_samples, n_features)
      Training data, where `n_samples` is the number of samples and
      `n_features` is the number of features.
  
  Returns
  -------
  self : object
      Returns the instance itself.
docstr_tok: ["Placeholder","for","fit",".","Subclasses","should","implement","this","method","!","Fit","the","model","with","X.","Parameters","--","--","--","--","--","X",":","array-like","of","shape","(","n_samples",",","n_features",")","Training","data",",","where","`","n_samples","`","is","the","number","of","samples","and","`","n_features","`","is","the","number","of","features",".","Returns","--","--","--","-","self",":","object","Returns","the","instance","itself","."]
code: def fit(self, X, y=None):
      """Placeholder for fit. Subclasses should implement this method!
  
      Fit the model with X.
  
      Parameters
      ----------
      X : array-like of shape (n_samples, n_features)
          Training data, where `n_samples` is the number of samples and
          `n_features` is the number of features.
  
      Returns
      -------
      self : object
          Returns the instance itself.
      """
  
file_path: scikit-learn/sklearn/decomposition/_base.py
imports: from abc import ABCMeta, abstractmethod
  import numpy
  from scipy import linalg
  from scipy.sparse import issparse
  from ..base import BaseEstimator, ClassNamePrefixFeaturesOutMixin, TransformerMixin
  from ..utils._array_api import _add_to_diagonal, device, get_namespace
  from ..utils.sparsefuncs import _implicit_column_offset
  from ..utils.validation import check_is_fitted
label_desc: Use image node_id 3 for calling the _BasePCA obj's underlying member method code with example usage: obj.fit(X, y) without return types